This invention relates to a method and apparatus for operating an internal combustion engine with a fuel supply apparatus and a lambda-control apparatus for the control of the fuel air-mixture based on a certain value where the fuel quantity to be supplied to the engine is regulated in accordance with the signals representing the speed (RPM), engine load, and exhaust gas composition.
It is common practice to activate the lambda-control apparatus after a certain temperature of the exhaust-gas sensor has been reached, after which the air-fuel mixture is adjusted to .lambda.=1. It has been demonstrated that this procedure leads to unsatisfactory results particularly at low starting temperatures even though the specified temperature of the exhaust-gas sensor is rapidly reached since the air intake pipe to the engine is still so cool that the fuel component of the mixture condenses on the inner walls of the internal combustion engine and no optimum mixture exists in the combustion chamber. This, in turn, impairs both the ignition characteristics, the engine smoothness as well as the exhaust gas composition.